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HXRSS Design Status. P. Emma et al Feb. 25, 2011. Figure 1 of the paper…. “…introduces no path delay of x-rays”. Taper works better. 1- m m rms e - pulse length (3 fs). Taper last 10 undulators for 100-GW power level. HRXSS Physics Requirements Document: - PowerPoint PPT Presentation
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HXRSS Design Status
P. Emma et alFeb. 25, 2011
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Figure 1 of the paper…
Taper last 10 undulators for 100-GW power level
1-mm rms e- pulse length (3 fs)
“…introduces no path delay of x-rays”
Taper works better
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HRXSS Physics Requirements Document:Electron & FEL parameters (e.g., 20 pC)Chicane parametersMagnet requirementsCrystal with position/angle controlsVacuum chamber requirementsBragg diagnostic requirementsAll tolerances
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2.6 mm
60 cm 60 cm
New HXR Self-Seeding Chicane for the LCLS Undulator (~U12)
QUAD
QUAD
3.4 m
existing undulator segment
QUAD
QUAD
BFW
|B0| ≈ 3.34 kG, R56 = 12 mm, cDt = 6 mm, hmax = 2.6 mm, q = 2.67 mrad
ELEVATION VIEW
PLAN VIEW
QUAD
QUAD
Remove one segment and add chicane (1.5 Å, 13.64 GeV)
BFW
BPM
BPM
BPM
e-
BFW
0-80 mm
chicane raft
B3B1 B4B2
36cm
36cm
36cm
36cm
3.20 m
58 cm
Beam Finder Wire
e-
crystal
provides 0-40 fs delay
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32 mm
alignment stage
chicane raft
motor
0 - 80 mm
80 mm
e- beam with dipoles ON & inserted e- & x-ray beam with
dipoles retracted
existing girder
356 mm
8 mm
alignment stage
chicane raft
existing girder
existing horizontal slider
cross-sectional view elevation view
x-ray beam with dipoles inserted
2.6 mm
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vq
CCD camera
YAG screen (>0.3-mm thick?)
crystaltransmitted x-raysincident x-rays
Bragg reflected x-rays
0.1 mm
vacuum window
f
FEL Wavelength Range: lr = 1.4 to 1.7 Å (somewhat arbitrary)Bragg Crystal Angles : q = 51.7° (1.4 Å) to 72.4° (1.7 Å)Camera Viewing Angles : f = 2(p/2 - q) = 35.2° to 76.6° (>41°)*
* Compromise: Allow camera viewing only from 1.4 to 1.6 Å or f = 77.6° to 51.4° (~27° range)
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HXRSS Chicane Dipole Magnet Design is ReadyD. Walz• 0-6 A• 576 main coil turns• ±1% trim coils (±6 A)• No water cooling• ~50 W/magnet• 0.02° C tunnel rise
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Possible 4-Axis Diamond Positioning System
D. Shu (ANL)
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Possible HXRSS Layout at U15 (or U16)
J. Amann (SLAC)D. Shu (ANL)
Sliding raft to move all 4 dipoles IN or OUT (8 cm)
Crystal chamber (ion pump must move)
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Issues
Do we place it at U15 or U16 (need ~1 GW seed)?Will we lose power in SASE mode (25% so far)?Can the chicane be tweaked to fix the phase error?Is a 0-40 fs chicane OK (i.e., only 20-40 pC supported)OK to have 2.6-mm crystal-to-electron hor. clearance?Commissioning plan started, but needs more thought.Existing LCLS monochromator only measures 10-4 BW. This will have to suffice OK for now?What will go wrong and how do we avoid it?